1. Field of the Invention
This invention relates to a piezoelectric element including a BiFeO3 piezoelectric film, an ink jet recording head, an ink jet printer, a surface acoustic wave element, a frequency-dependent filter, an oscillator, an electronic circuit, a thin film piezoelectric resonator and an electronic apparatus.
Priority is claimed on Japanese Patent Application No. 2003-181153, filed Jun. 25, 2003, and Japanese Patent Application No. 2003-308967, filed Sep. 1, 2003, the contents of which are incorporated herein by reference.
2. Description of Related Art
An ink jet printer is known as a high-resolution and high speed printing printer. The ink jet printer is provided with an ink jet recording head which comprises a cavity with a variable internal volume, and, in the ink jet printer, printing is carried out by ejecting ink droplets from nozzles while the head scans. A piezoelectric element made of ceramic as represented by PZT (Pb(ZrxTi1-x)O3) is conventionally used as a head actuator in the ink jet recording head for such an ink jet printer (see, e.g., Japanese Unexamined Patent Application, First Publication No. 2001-223404).
It has been confirmed in recent reports that BiFeO3 as a ferroelectric material has a high ferroelectric characteristic of dielectric polarization moment Pr of 60 to 70 μC/cm2 (see, e.g., Science, Vol. 299, 1719–1721, 2003). For this reason, BiFeO3 is a good piezoelectric material and BiFeO3 is anticipated to be used. In this report, upper and lower electrodes between which a ferroelectric layer is sandwiched are made of SrRuO3, and the ferroelectric layer made of BiFeO3 has a perovskite structure in a tetragonal system. Characteristics of a surface acoustic wave element, a frequency filter, an oscillator, an electronic circuit, and the like are expected to be improved, and therefore this new piezoelectric material is anticipated to be employed therein.